QuestionI have a Mercedes 240D that just recently started having starting problems ever so often. I would start the car and it would run fine, but every now and then when I go to restart it, it won't start. A friend of mine is a diesel mechanic, and he got it to start by pumping the primer pump while cranking the engine at the same time. I tried the same technique when it wouldn't start, and I can get it to start and run fine. After starting the car by using the technique it will run and start just fine for a while. The problem is that I never know when it will start or not start. Is the primer pump to blame, or is there something else that I'm overlooking? Please help me with any possible answers. Thanks.
AnswerIs the air filter clean or plugged with oil sludge?
Is the fuel filter by the primer/lift pump clean/clear or black particles/solid black?
Are all fuel hoses fresh and dry, or old/cracked and damp?
When you run the engine, then open the fuel fill cap, do you hear a whoosh of escaping air or sucking hiss of vacuum?
The plastic fuel tubes to/from injection pump, are they clear/clean white, or brittle red/black?
Have you looked under the body and traced the fuel lines back to the tank, looking for any damp spots, massive corrosion on lines or brittle/weeping rubber hose?
Have you removed the vacuum line from shut off valve on injection pump, and tried starting?
#1. Replace fuel filters http://www.mercedesshop.com/shopforum/showthread.php3?t=105344
#2. Use biocide in fuel tank, keep spare filters and needed tools in the car for road side changes http://www.mercedesshop.com/shopforum/showthread.php3?p=723857#post723857
http://www.mercedesshop.com/shopforum/showthread.php3?p=823378#post823378
#3. Test glow plugs http://www.mercedesshop.com/shopforum/showthread.php3?t=104547&page=1&pp=15
http://www.mercedesshop.com/shopforum/showthread.php3?t=134695
If all of this fails, some of your possible issues could be:
#A. Plugged fuel tank screen.
#B. lift pump.
#C. Injection pump.
#D. Low compression = engine rebuild.
